Conventional vehicle suspensions employ a spring and shock absorber to isolate wheel motion from body motion. Advances have been made in suspensions by making the suspensions active. For example, in an active suspension system, a controlled force is introduced between the mass of a vehicle body (i.e., a sprung mass) and the mass of a wheel assembly (i.e., an unsprung mass) to achieve improved comfort and handling.
An active suspension system can include an actuator system having a rotary motor disposed on a drive shaft and a transmission mechanism associated with the rotary motor. During operation, the transmission mechanism converts the rotation of the rotary motor to a linear motion of the drive shaft along a single direction to adjust a position of the wheel assembly relative to the vehicle body.